Description of electoral system:

The Prime Minister is appointed by the governor-general having been judged by the governor-general to be capable of commanding the support of a majority of members of the House of Representatives.

In the Senate 76 members are elected through a single transferable vote (STV) proportional representation system to serve 6-year terms*. In the House of Representatives 150 members are elected through an alternative voting system to serve 3-year terms.**

* 72 members of the Senate represent the States (12 per each of the six states) and serve six-year terms, with half of these seats renewed every three years. The four remaining members of the Senate represent the two mainland Territories. Parties may present a Group Voting Ticket, by which they recommend to their supporters orders of preferences for the various candidates . Electors can cast a ballot in two ways. The first method is by marking a "1" in a party's box indicating they wish to adopt the party’s recommendation as their vote. These votes then counted as if the elector had ranked the candidates in the party-recommended order. Alternatively, electors may choose to rank candidates individually, from one to as many candidates as are on the ballot. If voters do not rank every candidate on the ballot, their votes will generally be invalid, though some allowance is made for the counting of votes on which only a limited number of mistakes have been made. Senate candidates must obtain a certain “quota” of votes to be elected. This quota is calculated by dividing the number of valid votes cast by one more than the number of vacancies being filled, and increasing by one the quotient so obtained (with any remainder disregarded). After counting all first preference votes, candidates who meet the quota are declared winners and their surplus votes are reallocated via a fractional transfer.

** Members are elected in 150 single-member constituencies spread among the 6 states and 2 mainland territories of Australia according to population. If electors do not rank every candidate on the ballot their ballot is considered invalid. Voting is compulsory.